On the one hand there is continual pressure on elevator designers to reduce the space required for an installation within a building, but on the other hand the installation must meet industry standards by ensuring that an adequate safety space is provided in the overhead and pit of the shaft for maintenance personnel working in the shaft. Traditionally, these safety requirements have been met by providing an extended shaft having the appropriate safety spaces permanently installed above and below the travel path of the elevator car.
There have been recent proposals to reduce the space required by an elevator installation by removing the permanent safety spaces and instead creating temporary safety spaces only when required. U.S. Pat. No. 5,773,771 describes such a system using bolts that extend outwardly from opposing sides of the elevator car to prevent the car from moving into a particular zone or temporary safety space. When maintenance is to be carried out within the shaft, the technician mounts the roof of the car and pulls a rod at the side of the car to trigger the bolts into their extended position. The technician can then move the car at a reduced, inspection speed along the shaft using an inspection control station. The travel path of the car is restricted as the extended bolts engage with corresponding steel plates mounted at specific positions on the guide rails and the required temporary safety space is thereby established.
The objective of the present invention is to simplify the procedure for performing maintenance operations within the shaft of an elevator installation. In particular, the invention seeks to overcome the need of the maintenance technician to remember to manually activate the bolts before commencing inspection speed travel using an inspection control station mounted on the car.